Agglomerating or cementing granular materials



- cementing substance.

Patented Oct. 23, 1923.

UNITED sTATEs PATENT OFFEE. I

THOMAS M. CHANCE, OF PHILADELPHIA, PENNSYLVANIA.

AGGLOMERATIN'G OR CEMENIING GRANULAR MATERIALS.

No Drawing.

- To all whom it may concern:

ing or cementing of granular materials such as coal, coke breeze, ores, concentrates and the like, by the use of a cementing material such as coal, or other solid hydrocarbons which have the property when heated of coking or of agglomerating into a coherent Anthracite coal or coke, consisting .of particles less than onehalf inch in diameter cannot readily be burned in furnaces adapted to the combustion of coarser fuels, especially when the fuel consists largely of particles one-eighth of an inch or less in diameter, because suflicientair for combustion can be forced through such a bed of fuel only by using an air pressure that tends to blow the finer particles out. of

the cpmbustion chamber. To overcome this recourse has been had to two methods in which the fuel is agglomerated by theuse of a cementing material. Bituminous coal has been thus used by mixing it with the fuel before firing, the heat of the furnace coking the bituminous coal, thus cementing the particles of coke or anthracite coal together before the temperature of the latter reaches that at which its combustion occurs. To efi'ect this by methods heretofore used requires the addition of a relatively large percentage of bituminous coal. In other methods of utilization the coal is briquetted by the use of a binder prior to its introduction into the combustion furnace.

In describing my invention I will describe its application to the making of briquettes from anthracite culm or dust which consists of fine coal (smaller than about or inch) rejected as waste in the preparation of anthracite coal for market, it being understood that other materials such as those above mentioned may be cemented in like manner. By employing aoombination of the improvements which I have invented I have succeeded in making briquettes of anthracite fines, typical of high-grade culm, and bituminous coal. of extraordinary hardness and strength, and

Application filed September 27, 1920. Serial No. 413,194.

capable of being subjected to rough handling without appreciable breakage. Tests to determine the strength oft his material under compression, using cylinders with a height about 1;} times their diameter, show breaking strengths varying from 1200 up to 8400 pounds per square inch. The strength varies with the character and composition of the materials used, their relative coarseness or fineness, the proportions in which they are mixed, the character of temporary binder used, the compression under which they are molded, the temper ature at which they are coked or baked, the character of the atmosphere in which they are coked and the time consumed in coking or baking. Briquettes made of the 1 same materials under the same. conditions show remarkably uniform strength, for example, one set of briquettes made with 7 5 per cent of anthracite fines and 25 per cent of lVestmoreland, Penna, bituminous coal (P'ittsburgh'bed) with about 3 to 4 per cent of Texas oil distillate as temporary binder, showed breaking strengths under compression of'7330, 7750 and 7820 pounds per square inch. Another similar set'coked at slightly lower temperature showed strengths of 5920, 6080 and 6160 pounds per square inch, and another set duplicating these conditions showed strengths of 5960 and 6070 pounds per square inch, while similar briquettes made in which 8 per cent of water was used to replace the oil as a temproary binder, showed strengths of 5500 to 6200 pounds per square inch. The material thus produced is very much stronger than anthracite coal or than the best grades of coke, which latter show compression strengths of 1000 to 3000 lbs. per square inch. Its specific gravity varies with the variables above noted, usually ranging from about 1.00 to 1.20. It is porous and therefore quick burning.

The several sets of briquettes above described were all made with about 74 to 75 per cent of anthracite fines and 24 to 2-5 pera bright red heat, and the second and third sets at an ordinary red heat, and those of the water binder series were coked at temperatures about the same as those of the oil binder series, the strength of the resulting briquettes being thus shown to be affected in greater or less degree by the character of temporary binder used and the temperature at which coking was effected. In making these briquettes the anthracite fines were so graded that they consisted of particles that varied in size from 60 mesh down to 120 mesh, being passed through a. 60 mesh sieve and having had removed material fine enough to pass through a 120 mesh sieve, and the bituminous coal consisted of finely ground material all of which passed through a 120 mesh sieve and containing also much finer material down to. and including more or less impalable dust. Other illustrations of composition of briquettes I have made are as follows; briquettes of fair strength made by molding ata pressure of 800 pounds per square inch and coking for minutes at a dull red, the briquettes bein of an eggette shape 15- to 15} inches in dlameter, and composed of 33.3 per cent of anthracite coal from 2; inch to 20 mesh, per cent of anthracite from 20 to 120 mesh and 16.7 per cent of bituminous coal smaller than 120 mesh, about 10 per cent of water being used as a temporary binder; eggette briquettes 1% by 2% inches in diameter, made with 80.75 er cent of a mixture ofv anthracite comprising sizes of 20 mesh to 120 mesh, and mesh to 120 mesh, with 19.25 per cent of bituminous coal smaller than 120 mesh, with 8 to 10 per cent of water added before molding, molding at pressure of about 800pounds per square lIlOll and coking 50 minutes at a dull red, these briquettes being drop ed from a height of 10 feet upon a hard yellow ine floor twice without injury, but brea ing into several pieces on the third drop; cylindrical briquettes, hard, bright and capable of taking a high polish, made of a mixture of 80 per cent anthracite sized between 6 mesh and 120 mesh sieves and 20 per cent of bituminous coal ground to pass through a 120 mesh sieve, mixed with 8 per cent of water and molded at low ressure in a tube 1%; inch in diameter and coked at a dull red temperature in tube for 25 minutes; massive agglomerated anthracite, made from a mixture of per cent of anthracite sized between 60 and 120 mesh, and 25 per cent of bituminous coal smaller than 120 mesh, with 8 per cent of water, placed in a pasteboard box 1?;x1x3% or 4 inches in a cold oven and brought up to an orange heat in about 40 minutes, which was strong enough to bear ordinary handling without serious breakage.

Many attempts have been made to utilize anthracite culm by coking with bituminous coal, and experiments have been'made also in briquetting a mixture of anthracite culm and bituminous coal and heating the briquettes to coke the bituminous coal.

I have discovered that to agglomerate or cement together granular materials of the above described types in such manner as to secure maximum strength of the finished product, both the material to be cemented and the material used as the cementing agent should be properly prepared. If the material to be cemented is inherently stronger than the cementing agent, then maximum strength will be attained when the particles of the stronger material are in more or less intimate contact and the cementing agent is less, or does not greatly exceed, in volume the volume of the pores or interstices between the particles of material to be cemented. If, however, the material to be cemented is inherently weaker than the cementing agent, then the strength of the finished product will be increased by increasing the percentage of the cementing agent. Failure to recognize these principles and failure to prepare the ingredients used in conformity therewith are the causes of failure to produce coked fuel and coked briquettes of satisfactory strength.

In the agglomerating by a cementing substance of materials of the above described types, the cementing substance may be considered. to act either as a cement to hold the particles together or as a cellular matrix with the individual particles embedded in its cells. In the latter case the cementing material should have a volume equal to or greater than the sum of the interstices, or the porosity, of the granular material; but if the cementing material merely performs the functions of a cement, then its volume should not exceed and advantageously may be less than the porosity of the granular material. I find that when the granular material consists of particles of relatively strong material, the greatest strength can be obtained in the finished product by close juxtaposition of the particles of granular matter and I attain this'end by introducing the cementing material in a very fine state of subdivision and insuificient quantity to insure a film of such substance between all adjacent particles of the granular material which is to be cemented or agglomerated. In other words, the cementing material ust be distributed throughout the granular, aggregate to form a series of films adhering to the contiguous particles, and not as layers separating these particles by an appreciable space or interval. If the cementing material is a solid such as bituminous coal, or

like substance, it must therefore be ground,

crushed or pulverized so that its individual particles will be relatively smaller than the individual particles of which the granular material consists. Unless the cementing material is thus finely comminuted, its coarser particles will separate the particles of the granular materials by an appreciable space and thus increase the porosity of the granular material. As an illustration of this principle, I have made briquettes of anthracite coal ground or crushed to pass through a 20 mesh sieve and mixed it with.25 per cent by weight of bituminous coal similarly ground to pass through a 20 mesh sieve and have made other briquettes of the same materials except that the per cent of bituminous coal was ground to pass through a 120 mesh sieve, the materials in both cases being thoroughly mixed, moistened with about 8 or 10 per cent of water and molded in a briquette press under the same pressure and coked orbaked at the coking temperature of said bituminous coal, at a red heat, in identical containers (to exclude oxygen) for the same length of time at the same temperature; the first set of briquettes were relatively weak and friable and when tested broke under, compression at 400 to 600 pounds'per square inch, while the second set made with the finely ground bituminous coal were hard and strong and broke at 1300 to 1400 pounds per square inch. Ihave made briquettes also from the same anthracite and bituminous coal, both of which were ground to pass through a 120 mesh sieve, using the same proportions as to weights, the same pressure and the same coking temperatures as i the other experiments described in this paragraph, and found they were uniformly weak and friable and broke under compression at about 300 to 400 pounds per square inch, still further illustrating the requirement that to produce strong briquettes the cementing substance must be so comminuted that its particles will be materially smaller than those of the granular material which.

is to be cemented or agglomerated.

My invention is therefore based primarily upon the improvement which consists in the use of a coking material composed of particles materially smaller in size than those of the granular material which is to be cemented or agglomerated, said coking material being in quantity sufiicient to substantially fill the voids between the particles of the granular material. By using this method I.have sucessfully briquetted magnetic iron ore concentrates ranging from 40 to 100 mesh by the use of bituminous coking coal ground to pass through 120 mesh.

A fbrther improvement which I may employ 1n the cementing or agglomeration of materials of the above enumerated types, consists in the preparation of the granular material to reduce its porosity and increase its strength, butI do not herein claim this improvement except in combination with the invention herein disclosed, as I have made 1t the subject of another application for patent filed simultaneously herewith'on September 27, 1920, Serial No. 413,196.

The strength of many natural and some artificial products is increased by crushing to relatively small size, that is, the small particles may have greater relative strength to resist crushing thanlarge particles. This is doubtless due to the presence of natural cleavage or fracture planes in the larger pieces; thus, while the strength of anthracite coal in cubes of one or two inches in size usually ranges from 2000 to 8000 pounds per square inch, I have found by crushing tests that cubes of 2; inch or inch show crushing strengths of 10,000 to- 18,000 pounds per square inch,-in other words, the smaller pieces are relatively stronger than the large pieces. Hence one of the improvements which I may employ contemplates crushing the coarser particles for the purpose of increasing the average strength of the aggregate. In preparing the granular material by grading as to the size of its particles, any crushing which may be necessary forthat purpose will tend to increase the strength of the aggregate by increasing the relative strengths of the particles of which it consists. Followed to its logical conclusion, this premise would imply that the strongest aggregate would be obtained by crushing all of thegranular material to very small size, but this is not practicable because the reduction of the particles to very small size greatl increases the sum of the superficial sur aces of these particles, and as these surfaces should be coated with a film of the cementing material, the quantity of the cementing material necessary to coat. these surfaces becomes relatively toolarge to comply with the requirements essential to the production of a-finished product of satisfactory strength, because the thickness of this film of cementing material between the individual particles tends to separate them by an interval that, compared with the size of the particles, is relatively too great. If the size of the particles of granular material be very small, it becomes practically impossible to comminute the cementing substance to the still smaller size necessary, or to secure such complete and thorough admixture of the materials so prepared as to insure uniform distribution of the cementing substance throughout the mass. I am' aware that in the manufacture of briquettes the materials have been crushed or ground to varying degrees of fineness for the purpose of securing a product of uniform texture, but I believe crushing to produce grading as above described and to increase the strength of the granular material is a new and useful improvement in the art. I do not, however, herein claim this improvement except in combination with the invention herein disclosed, as I have made this the subject of another application for patent as already stated.

hen the particles of the material to be agglomerated are angular in form, it is evident that they cannot be firmly cemented together to produce a relatively strong product, if they are merely cemented together by a film of cementing material, because many of the points of contact will consist of a sharp edge or a sharp point of one particle in contact with a fiat surface of another particle, and the contact will consist merely of a point or a line. If in such case the fiat surface of the particle be coated with a mere film of a cement, angular particles in contact with such flat surface, where such contacts are merely lines or points, will not be ccmcnted-to the first particle in such a way as to develop material strength, and to insure a union between such particles that will be relatively strong, the cementing material must be built up around such point of contact, so that the sharp corners or edges of the particles are embedded in the cementing material, which thus forms a matrix which adheres to the sharp points or edges by a much greater area, than the area of actual contact of particle to particle. It will therefore be understood that to produce an agglomerated product of satisfactory strength, it becomes necessary to use more of the cementing material than that which would be required to merely coat the surface of such angular material with a thin film of the cementing substance. and that the strength of the product will be at a maximum. when the cementing material is present in sufficient quantity to form a matrix that practically fills the voids or interstices between the individual particles which are to be cemented or agglomerated.

To secure close juxtaposition of the particlcs of granular material with each other, and with the cementing substance, the mixture may be compressed. Moderate pressure .exerted upon a dry mixture of the described type does not however make much change in the relative position of the particlcs comprising the mixture. If, how ever. the mixture be moistened with water, oil, or other liquid, the particles seem to slide more readily upon each other, the liquid doubtless acting as a lubricant to reduce interstitial friction, and the mass is materially reduced in volume with corresponding increase in density. A further function of such liquid is its property of holding the material together by surface tension, "molecular attraction, capillarity, or whatever term may be used to designate the force that causeswetted particles to adhere to each other.

The quantity of cementing material to be used to attain the best results depends upon the porosity or percentage of voids in the material to be agglomerated or cemented, and upon its relative coarseness or fineness. I have successfully made briquettes of anthracite coal in which the particles of anthracite coal varied from 1; inch mesh down to 120 mesh, grading the percentages of coarse and fine particles as described in suitable proportions, and usin as the cementing material mixed therewith, from 7.5 per cent up to 30 per cent of finely round cok ingcoal. The strength of the material usually increases with the percentage of coking coal up to about 25 to 30 per cent. If too large a quantity of coking coal be used the briquettes are likely to swell or suffer deformation, with the formation of blow holes or shrinkage cracks.

The presence of relatively coarse anthracite, that is, particles i to mesh, tends to reduce the strength of the resulting product, and the presence of much anthracite dust, that is, particles smaller than or 120 mesh, also tends to reduce the strength. Hence, in the introduction of coarse ma terial to reduce the porosity of the mass, regard should be had to the relative strength of the particles so added; otherwise the final product may be weakened by these coarser particles.

The coking coal used as a cementing material should, as already stated, consist of particles materially smaller than those com posing the mass material to be cemented. I have obtained excellent results by using bituminous coal ground to pass through a 100 or 120 mesh sieve, containing of course a large quantity of material of 200 and 300 mesh or even finer, as the cementing material to agglomerate anthracite coal that had passed through a 60 mesh and over a 100 or 120 mesh sieve, and to agglomerate anthracite coal most of which was 60 to 100 mesh but which in some cases contained some 20 mesh material, and in. others contained anthracite coal that had passed through 1} or inch mesh sieves, and over 10 or 20 mesh sieves. In mixtures of these last described types the presence of the coarser coal particles assists in obtaining good results with relatively low percentages of the coking coal; hard and strong briquettes being produced when the bitumi nous coal forms but from 14 to 17 per cent by weight of the mixture, and fairly coherent briquettes being made from mixtures containing as little as 7.5 to 10 per cent of the bituminous coal.

The strength of briquettes depends to some extent upon the compression to which they are subjected. I have molded briquettes of these several types at pressures ranging from 200 pounds per square inch ill) - 2500 pounds up to 10,000 pounds or more per square inch. While no exact rule or law has been worked out b which the efiect of pressure used in mol ing can be predetermined, I have found that briquettes molded at 500 to TOO-pounds pressure per square inch developed strengths upon coking of 2300 to per square inch, while briquettes made of the same material but which were molded at a pressure of 7000 to 7500 pounds per square inch, developed strengths of 4000 to 6000 pounds per square inch, thus showing, in "these cases'at least,

- combustible matter, chiefly hydrocarbons,

that a great increase in the compression pressure produced a relatively smaller increase in the strength of the resulting product.

In agglomerating or cementing materials by the method I-have described, when the cementing material is one with a property of coking, the temperature used to eliect coking materially affects the strength oft-he resulting product. In the manufacture of anthracite briquettes it may be desirable to use a relatively low temperature in order to retain a considerable proportion of volatile combustible constituents in the finished briquette. I have made many briquettes by coking at a dull red, or barely visible red, heat, and 'in some cases even below a visible red, and the briquettes produced have been sufliciently hard and strong to bear handling without disintegration. briquettes the temperature has been raised suflicientl to drive off most, if not all, of the illuminating hydrocarbons (which are driven ofi' from the coking coal forming the cementing material) at relatively low temperatures. I have thus made briquettes which retain 5 per cent or more of volatile but which may in part consist of hydrogen. These briquettes generally have a crushing strength from oneebalf to two-thirds the strength which is attained if the coking be conducted at a bright red or orange heat, or at a heat suflicie tto drive oil nearly all of the volatil combustible matter. These results indicate that where the maximum crushing strength is desired, as in the case of metallurgical fuel, the coking should be finished at relatively high temperature; in other words, at a temperature comparable to that used in the commercial manufacture of coke. W here, however, there does not exist any reason why maximum strength is necessary or desirable, coking can be done at a much lower temperature. The advantages of coking at lower temperature are a reduction in the cost of the coking process due to operation of the coking or baking ovens at a lower temperature, a reduction in the time necessary for the completion of the cokin process and an 1ncreased fuel value of film product due to the In making these retention of the combustible volatile matter. There is also some advantage in the domestic use of briquettes so made due to the free burning nature of briquettes containingan appreciable percentage of volatile combustible matter. It is, however, in many cases desirable that the coking should proceed far enough to expel the illuminatmg hydrocarbons which are the cause of the smoke and soot in burning bituminous coal, thus producing a briquette which is practically smokeless.

Another application of my invention may be found in the use of lignite as a cementing materlal to be used in agglomerating or cementing anthracite coal, coke breeze and the like It is possible to produce hard and firm brlquettes from some lignites without the addition ofany cementing material, the lignite itself when subjected to the very high pressure in the briquetting presses used for this purpose becoming consolidated into a relatively'hard and firm mass able to withstand handling and transportation without objectionable breakage. It has been assumed that these lignites contain some substance (or substances) which, by the heat developed during compression in the brlquetting press, is used or softened, and acts as a cement or binder to consolidate the mass. It will be readily understood that any material having this property and developing sufficient strength may be usefully employed in carrying out my method of agglolmeratlng or cementing granular materia s.

It will be understood that the time required for agglomerating materials when a coking coal is used as the cementing material, will'depend upon the volume or mass of material introduced into the coking or baking oven, and u on whether the material is to be produce in massive form suitable for metallurgical use, or in the form of large or relatively small brie uettes for steaming or for domestic use. A n the manufacture of briquettes it is especially desirable to reduce the time required for coking to a minimum, because the process is not only cheapened thereby, but the coking can usually be completed with less loss of volatile combustible matter than where the coking period is prolonged. In the case of small briquettes weighing from 1-} to 2 ounces, I have obtained satisfactory results by coking for periods of from 15 to 25 minutes in a muiile furnace heated to a dull red heat. In manufacturing on a large scale the time required for coking of such briquettes may perhaps be materially reduce it below these figures, but I not able to state with exactness the time required to produce the most satisfactory results, as this will vary with the character of the materials used, the size of the briquettes and the be increased by manipulation ofthe materials during inanufacture.

It will be understood that if coking or baking of the cementing material be employed it should be carried out in a non-oxidizing atmosphere. After the temperature rises to a point where volatile combustible gases are given off, the gases soproduced will of course furnish a non-oxidizing atmosphere, and this will continue during the baking or coking period. It is, however, important that oxygen be excluded from the coking or baking ovens so far as possible. In the early stages, during which the briquettes are becoming heated, the gases or vapors given oil by the temporary binder used, whether this be oil or water, will of course tend to expel atmospheric oxygen, so that the briquettes will be surrounded, if water he used as the binder, by an atmosphere of water vapor, or if oil be used as a temporary binder, by an atmosphere of vapor of the oil so used. In the manufacture of most of the briquettes made, I have coked or baked them in a cylindrical sheet iron container with a lid or cover having a slip fit. The molded briquettes were placed within such container and the container introduced into a mufiie furnace as before described. The looseness of fit of the cover of these containers permitted the escape of steam, volatile hydrocarbons and gases given oii during the coking process, so that the briquettes as made were, after the coking process commenced, continuously in an atmosphere consisting of the volatile hydrocarbons given all: by the coking coal forming the cementing material, and the presence of these gases in the container would permit only very small quantities of oxygen to gain access to its interior, thus simulating the conditions present in the interior of by-product or retort coke ovens.

In the making of small briquettes pressure is generally an essential part of the molding process, and the use of a. temporary binder will usually be found advantageous. it is, however, possible in some cases to mold briquettes of sufiicient strength to bear handling during manufacture, without the aid of a temporary binder, and thus to produce a. product sutlicientlr strong to bear some handling without objectionable breakage. Aoglomerated fuel suitable for steam making and similar uses, and perhaps for smelting, may be. made by the use of my invention withoutthe application of pressure prior to coking, the use of a. temporary binder, or'special gradingof the granular material to be agglomerated, but generally speakingthe strength of the product will pressure prior to coking, by the use of a temporary binder and by preparation of the granular material as to size. I have, however, made a fair grade of agmuse-a glomerated or cemented fuel from anthracite fines mixed with 15 to 25 per cent of more finely ground bituminous coal, with-- out the addition of a temporary hinder, the application of pressure or grading of the granular aggregate as to the size of its particles,

In the examples above given in which graded materials containing coal inch and 6 mesh, between 20 and 120 mesh and between 60 and 120 mesh were agglomerated with bituminous coal ground to pass through 120 mesh and which contained all the liner material produced by such grinding, including the impalpable powder or dust so made, the number of particles of the cementing material was in ei ery case very much greater than the number of particles of the coal V that was agglomerated, the number of pan ticles in a given quantity of material theoretically increasinginversely as the cube of the diameter of the particles. For ex= ample, a given weight of 20 mesh size will have theoretically and approximately 6% times'as many particles as many particles as an equal weight of 5 mesh particles; the same weight of 80 mesh size will similarly contain 64 times as many particles as the 20 mesh size and {i096 times as many particles asthe 5 mesh size; and 160 mesh size will contain 8 times as many particles as the 80 mesh size, 512 times as many particles as the 20 mesh size and 32768 times as many particles as the 5 mesh size, so that it a graded mixture be made consisting); of 25 per cent of anthracite coal averaging 20 mesh. 50 per cent of anthracite coal averaging 80 mesh and 25 per cent of bituminous coal averaging 160 mesh, every unit of such mixture containing 1 piece of 20 mesh coal, will theoretically contain 128 pieces of 80 mesh coal and 512 pieces of 160 mesh bituminous coal, the particles of bituminous coal there fore out-nun1bering the particles of anthracite coal about ito 1.

in carrying out the various applications of my invention the details in each case should be variedto meet the requirements of the service, the character of fuel desired, and the shocks and attrition to which it may be subjected in handling, transportation'and during combustion, sufiicient strength to bear stresses and attrition being desirable if not essential. These requirements are at a minimum when the agglomerated fuel is burned without removal from the furnace in which agglomeration is affected and are at a maximum Whenlong distance transpon tation and repeated handling and rehandling are unavoidable, as in fuel made for export to foreign countries. The quantity of cementing material to meet these require ments, ending as to size, compression before coking, the use of a temporary binder and the temperature at which agglomeration is efi'ected can be varied as above described, the advantage of my invention being that in every case the necessary strength can be secured with a smaller quantity of the cementing material than with any method heretofore used, and in some cases, such as in direct firing, especial grading, compression and the use of a temporary. binder may not always be necessary to secure satisfactory results. 7

Wh1le the manufacture of a fuel by agglomerating or cementing anthracite fines, coke breeze and the like is the most .obvious application of my invention, the material s0 produced has characteristics that may fit it for other use. As already described this material may thus be made of great strength, as shown by briquettes I have made with a crushing strength of from 1200 up to 8400 pounds per square inch. It may be possible thus to produce material stronger than any I have yet made. This material is quite porous and may therefore be suitable for use as a filtering medium; it can be molded and produced in almost any desired shape or form; it is of light weight, usuall from 60 to 70 pounds per cubic foot, its lightness and strength fitting it for use as a structural material; it is not attacked by ordinary acids or alkalis and is infusible except at extremely high temperature. Such properties may adapt it to many;industrial uses.

In this specification and the claims hereof the terms materially smaller and appreciably smaller used in describing the relative size of the particles of coking material, are not intended to mean that all of the particles of coking material should or must be smaller than all of the particles of the granular or non-coking material, these terms being used to mean that the average size of the particles of coking material shall be materially or appreciably smaller than such as coal, or other solid hydrocarbons,

and the like, which when heated have the property of coking or agglomeratingl into a coherent cementing substance.

Having described my invention I claim: 1. A process of agglomerating non-coking material to form a product cemented by coking coal, whichconsists in mixing a mass of non-coking material of a definite grade, the coarsest particles of which non-coking material comprise not more than 40 per cent of the final mixture, with a mass of coking coal, the average size of the particles of said coking coal being materially smaller than the average size of the particles of noncoking material, and in heating the mixture to a temperature suflicient to coke the said coking coal.

2. The process of claim .1, in which the non-coking material constitutes at least 70 per cent of the total mixture.

3. The process of claim 1, in which the average size of the particles of coking coal is not larger than the average size of particles that will pass through a 120 mesh sieve.

In testimony whereof I have hereunto signed my name at Philadelphia, Pennsylvania, this 24th day of September, 1920.

THCMAS M. CHANCE.

Witnesses:

J. H. QUINN, CARL K. SCHULZE. 

